Percussive tool



L. C. BAYLES AND F. M. SLATER.

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UNITED STATES PATENT OFFICE.

LEWIS C. BAYLES AND FRED. M. SLATER, OF EAS'I'ON, PENNSYLVANIA, ASSIGNORS TO INGERSOLL-RAND COMPANY, OF JERSEY CITY, NEVT JERSEY, A CORPORATION OF NEW JERSEY.

PERCUSSIVE TOOL.

Specification of Letters Patent.

Patented Mar. 7, 1922.

To all whom it may concern:

Be it known that we, LEWIS C. Barnes and'Fnnn. M. SLATER, both citizens of the United States, residing at Fasten, in the county of Northampton and State of Penn sylvania, have invented a certain new and useful Improvement in Percussive Tools, of which the following is a specification.

This invention relates to fluid operated percussive tools, but more particularly to a hammer drill having a reversible piston controlled by a fluid actuated valve and provided with an independent motor for roating the drill steel. By a reversible piston, we mea a piston having a main head and extensions or shanks extending in opposite directions, but of the same size and dimensions, so that either shank may be utilized for delivering the blow uponan anvil or upon the drill steel, and this reversibility is sometimes an advantage in case for instance, one shank becomes chipped or broken. The piston may then be removed and reversed in the cylinder and the drill operated continuously without waiting to renew the entire piston.

o prefer to construct each shank or extension of the same uniform diameter throughout, without necks or reduced portions. as forming a stronger and more serviceable construction for the work intended to be performed, and with such type of tool we provide a valve for controlling the admission of fluid to the intermittently supplied portions of the cylinder, in this case in front of and behind the piston head. Fluid pressure is preferably constantly maintained on the rear surface of the rearwardly extending shank forming a forwardly driving pressure area.

For increased efiiciency, we. also prefer to use the type of differential controlling valve patented by F. M. Slater, one of the present applicants, on December 31. 1918, by U. S. Patent No. 1,289,285, in which anxiliary exhaust means from each end of the cylinder are also controlled by the valve,

although we do not confine ourselves to this particular type of valve.

Likewise, any suitable type of motor may be used for the independent rotation, al though we prefer the turbo type and in the form of the invention illustrated we have shown a turbo motor having epicyclic gearing as a convenient construction, this motor, however, being in itself a separate invention not herein claimed.

The invention is illustrated in one of its preferred forms in the accompanying drawings in which Figure 1 is a side view partly in longitudinal section of a tool embodying the invention,

Figure 2 is a transverse sectional view on the line 22 of Figure 1 looking in the direction of the arrows,

Figure 3 is a top plan view partly broken away and partly in horizontal section on the line 3-3 of Figure 1,

Figure 4 is an end view of the front end partly broken away and partly in transverse section on the line l4; of Figure 1, and

Figures 5 and 6 are diagrammatic views showing the piston at the forward and rear ends of its troke.

Referring to the drawings, the cylinder A is formed with a forward bore 13 of larger diameter and a rearward here Q of smaller diameter. The reciprocating piston, of a form dependent upon valve control, is provided with an enlarged main head D and re duced shanks E and F, both of-wliich shanks have smooth unbroken exterior cylindrical surfaces and are of substantially the same length and of equaland uniform diameter throughout, so that either one is adapted to fit and move in direct sliding contact with either the rearward. smaller bore C, or the bore G of the same diameter as the bore U, in the bushing H which forms forward piston guiding portion of the cylinder, although it is to be understood that the mcmber H appearing as a bushing may be formed as part of the cylinder and the smaller rear bore C may be contained in a bushing inserted at the back end of the cylinder. The piston may thus be reversed in the tool if necessary or desirable with out altering the operation of the tool. and by making the shanks of the same uniform. diameter they are each better able to withstand impact without breaking. Reduced necks or cutaway portions as in valveless tools are avoided and the distribution of motive fluid to the. cylinder chambers is controlled by a suitable fluid pressure actuated valve J to be described cooperating with the piston.

tension or shank F and the drill steel L,

to receive the impact of the hammer, although this anvil may be omitted if desired and the blow struck directly on the steel. One of the important advantages of the construction shown resides in the fact that a non-reversible piston having a heavier forward hammer extension F of larger diameter than the rearward extension E may be used if desired in the same tool without affecting the operation, by substituting a bushing H having a l rger bore adapted to receive the larger hammer extension.

The front end of the tool may be constructed in any usual and suitable manner, in this instance provision being made for imparting rotation to the drill. steel. by means independent of the reciprocating piston. Asshown, the anvil K is contained within a rotating sleeve Ov having gear teeth P meshing with the pinion Q on tie shaft R driven by a suitable motor preferably at the back end of the tool. The drill steel is held in the chuck S rotating with the sleeve O and the front head T is secured to the cylinder by the spring pressed cap U and the usual bolts V.

Motive fluid is admitted to the cylinder through an inlet V controlled by a suitable throttle valve X which may also control the lubrication as well understood. Fluid pressure is preferably although not necessarily, constantly maintained on one of the forwardly driving pressure areas of the piston, in this instance against the rear end of the rearward shank E. by means of the port Y communicating with the inlet V.

The admission of motive fluid to the forward bore B of the cylinder both in front of and behind'the main piston head D is preferably controlled by the valve J which is substantially similar to the valve shown in U. S. Patent No. 1.289.285 referred to. The valve 5 in this instance is located in the valve chamber Z conveniently extending transversely at one side of the cylinder. The valve .l is provided with differential pressure areas and in this instance is formed with two head portions 0. and 7) of different diameters connected. by a reduced neck of As shown, the smaller head 7; slides within a chambered bushing a. The central section of the valve as shown is hollow at e opening outwardly through the smaller hea d 7 in communication with the exhaust passane f open to atmosphere. The larger head a is provided with a leak port ,7 communicating with the hollow interior portion of the valve. Passages It also extend from the periphery of the larger head a to the hollow interior portion of the valve.

Motive fluid is admitted to the valve chamher Z through the passage controlled by 1 ,eoaesa the throttle valve X, and from the valve chamber a fluid passage 7: leads to the front 'end' of the forward bore B of the cylinder.

With the piston substantially at the end of its forward stroke as shown in Figures 1 and and the valve J in the position shown in l igures 8 and 5 motive fluid is admitted through the passage j. around the reduced neck portion 0 of the valve and through the passage 7: to the forward end of the forward bore B in front of the main piston head D. A main exhaust in this instance shown as a main exhaust port 0, 0 is provided for exhausting the cylinder in front of and behind the main head D. In order to admit fluid pressure to the forward bore 13 behind the main piston head D for the forward stroke. a fluid passage 79 is provided leading from the valve chamber Z to a suitable point at the rear end of the forward bore B. This passage p is shown opening into the valve chamber Z in Figures 3. 5 and 6- but is indica ted in Figure 1 in dot and dash lines because this passage is cut away owing to the longitudinal section on which the figure is taken. l Vith the piston in its rearward position as shown in Figure 6. and the valve J thrown to a position in which the larger head (1 is at the back end of the valve chamber. fluid may pass from the passage j to the passage 72 and into the forward bore B behind the piston head D in order to drive the piston forward.

The vz lve J is actuated by fluid pressure and for this purpose a piston controlled passage 9 extends fromthe valve chamber Z as shown in Figures 1, 3. 5 and 6 to a pointin the rearward smaller bore C of the cylinder. The port opening to the smaller borc (l is shown in Figure 1 in dot and dash lincs because it is in a portion cut away owing to the section on which the figure is taken. The passage q is open to fluid pressure only when the piston is at the forward portion of its stroke and as the piston moves rearwardly from the position indicated in Figures 1 and 5 the shank E covers the port for the passage (7 so that pressure in the valve chamber behind the larger valve head a may leak through the leak hole 5 and through the valve to the auxiliary exhaust port f. By the time the piston has reached its rearmost position the pressure exerted against the valve head a will have been rc duced sufficiently to be overcome by the pressure constantly exerted against the shoulders forming: the smaller dihmeters of the valve. and the valve will be thrown. to a position opposite to that shownin Figures 3 and The valve will be maintained in such position on the forward stroke of the piston until the, piston controlled pas-,

sage o is againv un overed by the shank E. admitting pressure against the larger pres sure area of the larger valve head cans-,

ing the valve to be thrown to the position indicated in Figures 3 and 5 and the cycle is repeated.

The valve J controls auxiliary exhaust means from both ends of the forward. bore 13, in order to lengthen the stroke and prevent air cusl'iioning, thus increasing the elliciency of the tool. In addition to the main exhaust through the port. 0, 0, an auxiliary exhaust is provided with the valve in the position shown. in Figures 3 and 5 through the passage p and through the ports 7b in the valve and through the valve itself to the exhaust port When the valve is thrown to its opposite position, the smaller head 5 uncovers the passage in opening into the valve bushing (Z so that an auxiliary exhaust is provided tl'irough the passage A: around the smaller head 1') of 1e valve to the euhaust port ,1. The an iliary exhaust. from either end of the forward bore B may continue after the main exhausthas been covered by the piston head.

The motor for in'iparting rotation to the drill steel may conveniently be enclosed in the motor casing r mounted atthe rear of the cylinder and forming the back head of the tool. In this instance the motor comprises epicyclie gearing operating on the turbo principle. A toothed gear 8 mounted eccentrically in the gear casing on the spindle t, and meshes with a revoluble internally toothed gear u concentrically mounted within the gear casing on the roller hearings o, which are preferably set into the channeled peripl'iery ot' the gear U. A battle or division plate w is inserted between the epicyclio gears and fluid pressure enters the gear casing through the inlet a and ex hausts through the outlet 1 The motor is geared to the driven shaft Iii through a suitable train of gearing including a pinion 2 on the spindle t meshing with the gear 3 having a pinion at meshing with the gear 5 on the end oi sha't't R. The gear casing r is closed. by means or the plate 6 and a suitable cap 7. The usual water tube 8 is ]')rovided extending through the spindle If and an outer cap 9 is secured over the end of the water tube by means of a bolt 10. Any suitable means may be provided for supplying water to the outer cap 9 and tube 8.

1. In a fluid operated percussive tool, the combination. of a cylinder having an enlarged bore, a bore of smaller diameter at one end and a piston guiding portion at the other end having a bore of the same diameter as the said smaller bore, a reciprocating piston dependent uponvalve control and having an. enlarged head and reduced shanks. said shanks having smoothunbroken exterior cylindrical surfaces and being of substantially the same length and of equal and uniform diameter, either one being adapted to fit and move in direct sliding contact with either the smaller bore or the piston guiding portion of the cylinder, means for exhausting the larger bore at each side of the piston head in its travel, means for maintaining substantially constant fluid pressure on the rearward surface of the rearwardly extending piston shank, and a fluid actuated valve for controlling the admission of motive fluid to the larger bore in front of and behind the main piston head.

2. In a fluid operated percussive tool, the combination of a cylinder having an enlarged bore, a bore of smaller diameter at one end and a piston guiding portion at the other end having a bore of the same diameter as the said smaller bore, a recipro eating piston dependent upon valve control and having an enlarged head and reduced shanks, said shanks having smooth unbroken exterior cylindrical. surtaces and being of substantially the same length and oi. equal and uniform diameter, either one being adapted to lit and move in sliding con tact with either the smaller bore or the piston guiding portion of the cylinder, means for exhausting the larger bore at each side oi the piston head in its travel, means tor admit ting fluid pressure behind the rearwardly extending piston shank, and a fluid actuated 'alve for controlling the admission of motive fluid to the larger bore in front of and behind the main piston head.

3 In a fluid operated percussive tool, the combination of a cylinder having an enlarged bore, a bore of smaller diameter at one end and a piston guiding portion at the other end having a bore of the same diametcas the said smaller bore, a reciprocating piston dependent upon valve control and having an enlarged head and reduced shanks, said shanks having smooth unbroken exterior cylindrical surfaces and being of substantially the same length and of equal and uniform diameter, either one being adapted to lit and'move in direct sliding contact with either the smaller bore or the piston guiding portion of the cylinder, means for exhausting the larger bore at each side of the piston head in its travel, means for maintaining substantially constant fluid pressure on the rearward surface of the rearwardly extending piston shank, a fluid actuated valve for controlling the admission of motive fluid to the larger bore in front of and behind the main piston head, and fluid actuated means independent of the reciprocating piston for imparting rotation to the drill steel.

4. In a fluid operated percussive tool, the combination of a cylinder having an enlarged bore. a bore of smaller diameter at one end and a piston guiding portion at the other end having a bore of the same diameter as the said smaller bore. a reciprocating piston dependent upon valve control and having an enlarged head and reduced shanks, said shanks having smooth unbroken exterior cylindrical surfaces and being of substantially the same length and of equal and uniform diameter, either one being adapted to fit and move in direct sliding contact with either the smaller bore or the piston guiding portion of the cylimler, means for exhausting the larger bore at each side of the piston head in its travel, means for admitting fluid pressure behind the rearwardly extending piston shank, a fluid actuated valve for controlling the admission of motive fluid to the larger bore in front of and behind the main piston head, and fluid actuated means independent of the reciprocating piston for imparting rotation to the drill steel.

5. In a fluid operated percussive tool, the combination of a cylinder having an en larged bore, a bore of smaller diameter at one end and a piston guiding portion at the other end having a bore of the same diameter as the said smaller bore, a reciprocating pis ton dependent upon valve control and having an enlarged head and reduced shanks, said shanks having smooth unbroken exterior cylindrical surfaces and being of substantially the same length and of equal and uniform diameter, either one being adapted to fit and move in sliding contact with either the smaller bore or the piston guiding portion of the cylinder, means for exhausting the larger bore at each side of the piston head in its travel, means for maintaining substantially constant fluid pressure on the rearward surface of the rearwardly extending piston shank, and a fluid actuated valve for controlling the admission of motive fluid to the larger bore in front of and behind the main piston head and for controlling auxiliary exhaust means from each end of the said larger bore.

6. In a fluid operated percussive tool, the combination of a cylinder having an enlarged bore, a bore of smaller diameter at one end and a piston guiding portion at the other end having a bore of the same diameter as the said smaller bore, a reciprocating snea piston dependent upon valve control and uniform diameter, either one being adapted to fit and move in direct sliding contact with either the smaller bore of the piston guiding portion of the cylinder, means for exhausting the larger bore at each side of the piston head in its travel, means for maintaining suhsta itially constant fluid pressure on the rearward surface of the rearwardly extending piston shank, a fluid actuated valve for controlling the admission of motive fluid to the larger bore in front of and behind the main piston head and for controlling auxiliary exhaust means from each end of the said larger bore. and fluid actuated means independent of the reciprocating piston for imparting rotation to the drill steel.

7. In a fluid operated percussive tool, the combination of a cylinder having an enlarged bore, a bore of smaller diameter at one end and a piston guiding portion at the other end having a bore of the same diameter as the said smaller bore, a reciprocating piston dependent upon valve control and having an enlarged head and reduced shanks, said shanks having smooth unbroken exterior cylindrical surfaces and being of substantially the same length and of equal and uniform diameter throughout, either one being adapted to fit and move in direct sliding contact with either the smaller bore or the piston guiding portion of the cylinder, neans for exhausting the intermittently supplied portions of the cylinder, means for maintaining substantially constant fluid pressure on one of the forwardly driving pressure areas of the piston, and a fluid actuated valve for controlling the admission of motive fluid to said intermittently supplied portions of the cylinder.

In testimony whereof, we have hereunto set our hands.

LEWIS G. BAYLES. FRED. M. SLATER. 

